The present invention relates to a semiconductor device and a technique of manufacturing it, in particular, to a technique useful when applied to manufacture a semiconductor device having copper wiring and a semiconductor device having wiring formed by using a damascene process.
Japanese Patent Laid-Open No. 2006-73569 (Patent Document 1) describes a technique of forming a SiCN film having a low Si—CH3 composition ratio over a SiCN film having a high Si—CH3 composition ratio by adjusting the flow rate ratio of trimethylsilane gas and helium gas. The document says that this technique makes it possible to suppress resist poisoning.
International Patent Publication No. WO2010/125682 (Patent Document 2) describes a technique of forming a SiCN film over copper wiring, and, over the SiCN film, forming a SiCO film. The document states that, at that time, the SiCN film is a copper diffusion prevention film having a function of preventing the diffusion of copper from the copper wiring, and that the SiCO film is a film of preventing the diffusion of amine generated in the SiCN film to thereby suppress the resist poisoning.